Ercker

Figure 9. Cupels, molds, and balls of ash, from Lazarus Ercker, Beschreibung allerfm-nemisten minemlischen Eitzt unnd Beickweicksaiten (Frankfurt am Main Georg Schwartz, 1580). (From the Roy G. Neville Historical Chemical Library, a collection in the Othmer Library, Chemical Heritage Foundation. Photo by Douglas A. Lockard.)...

Or so, at least, believed the chief superintendent of mines for the Holy Roman Emperor, Lazar Ercker. See Lazarus Ercker, Treatise on Ores and Assaying, trans. and ed. Anneliese Griinhaldt Sisco and Cyril Stanley Smith (Chicago University of Chicago Press, 1951). 

On Ercker in general, see Pamela O. Long, Openness, Secrecy, Authorship Technical Arts and the Culture of Knowledge from Antiquity to the Renaissance (Baltimore Johns Hopkins University Press, 2001), 188-91 and Ludmila Kubatova, Hans Prescher, and Werner Weisbach, Lazarus Ercker (1528/30-1594) Probierer,... 

Lazar Ercker in Prague to Herzog Julius in Wolfenbiittel, 3 May 1585, NStA Wolfenbiittel, 1 Alt 9, Nr. 394, fols. 1-2. 

Ercker, Lazarus. Beschreibung allerfiirnemsten mineralischen Ertzt unnd Berck-wercksarten. Prague Georg Schwartz, 1574. 

Lazarus Ercker, Beschreibung allerfurnemisten mineralischen Eitzt unnd Berckwercksarten, 1580 37... 

Cupels, molds, and balls of ash, from Lazarus Ercker, Beschreibung... 

The words wolfferam and wolffram were used a few years later by Lazarus Ercker, who assumed the mineral to be an arsenic and iron containing tin ore because of its association with tin. 

V Dufek, Lazarus Ercker von Schreckenfels, manuscript prepared tor the Symposium on Science and Technology of Rudolfinian Time, National Technical Museum, Prague (1997). 

FIGURE 5. Frontispiece from the final edition of Aula Subterranea by Lazarus Ercker (Frankfurt, 1736) depicting God seeding the earth with metals and their harvesting and refining by people. (The first edition of this book was published in 1574 the original blocks were employed to strike the plates in all subsequent editions.)... 

FIGURE 7. A sixteenth-century assay laboratory (Ercker, see Figure 5) ... 

FIGURE 8. A sixteenth-century machine washing alluvial gold ores (Ercker, see Figure 5). Gold s great density (19.3 g/cm permits its ready separation from other, lighter minerals. 

FIGURE 9. Making cupels from calcined, crushed bones ground into a paste with beer and molded. The oxides of baser metals such as iron are absorbed into the cupel while molten gold or silver remain on its surface (Ercker, see Figure 5). 

FIGURE 13. The use of parting acid (mostly HNO3) to separate silver from gold. Silver is soluble and gold is not soluble in this acid (Ercker, see Figure 5). 

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